1. Field of the Invention
The present invention relates to a liquid crystal elemental device production process. The device is suitable for use in color televisions, personal computers and the like. The invention also relates to a liquid crystal elemental device produced by the production process and a substrate which is a constituent member of the liquid crystal elemental device.
2. Related Background Art
With the advancement of personal computers, particularly, portable personal computers in recent years, the demand for color liquid crystal display devices has been increasing. It is, however, necessary to reduce the manufacturing cost of color liquid crystal display devices in order to make their use more widespread.
In a conventional production process of a liquid crystal elemental device, an elemental device for driving a liquid crystal, such as a TFT (thin film transistor), or an optical elemental device for coloring, such as a color filter, is provided on a pair of glass substrates which are transparent insulating substrates, and both transparent electrode and orientation film are then formed on each of the substrates. Spherical or cylindrical particles composed of silica, alumina, a synthetic resin or the like and having a particle diameter of about 3 to 10 xcexcm are then dispersed as a spacer on the whole surface of one of the glass substrates on which the transparent electrode and orientation film have been formed. The pair of glass substrates are superimposed on each other through the spacer thus formed with the transparent electrodes opposed to each other, and a liquid crystal is enclosed in a space between the substrates, thereby producing a liquid crystal elemental device.
However, since a state of transmission/shading varies in effective pixel portions according to display condition, each spacer is observed as a bright point upon shading when the spacer is formed with a colorless, transparent material, or as a black point upon transmission when the spacer is colored black. This has caused problematic display quality deterioration.
In order to solve the above problem, there has been proposed a process in which an orientation film is subjected to an orientation treatment and then coated with a photosensitive polyimide or photoresist to conduct exposure through a mask, thereby forming spacers composed of the polyimide or photoresist at portions other than effective pixel portions as shown in Japanese Patent Application Laid-Open No. 61-173221, Japanese Patent Application Laid-Open No. 2-223922 or the like. According to this process, the spacer can be formed at arbitrary places with an arbitrary density, so that unevenness of cell gap in the liquid crystal elemental device when a liquid crystal is enclosed can be improved. Japanese Patent Application Laid-Open No. 3-94230 describes a process for fixing a spacer comprising beads on a shading layer in a region other than effective pixel portions.
Besides, there have been proposed methods in which a very thick black matrix is used as a spacer (Japanese Patent Application Laid-Open Nos. 63-237032, 3-184022 and 4-122914), in which an overlapped colored resist is used as a spacer (Japanese Patent Application Laid-Open No. 63-82405), and in which a colored pattern is also formed on a black matrix to use it as a spacer (Japanese Patent Application Laid-Open No. 63-237032).
All the methods proposed above are methods making use of photolithography and hence have involved problems in that an expensive exposure apparatus is required, and a production line is elongated due to the introduction of a wet process such as development.
In the above improving methods, it is necessary to directly apply the photosensitive polyimide or photoresist on to an orientation film formed of a polyimide film subjected to an orientation treatment by a rubbing process or the like and remove an unnecessary portion thereof with a solvent or the like after exposure. These steps may markedly contaminate or alter the state of orientation of the oriented film in some cases, and so there is a possibility that the orientation of a liquid crystal injected into a liquid crystal cell may be made uneven.
It is an object of the present invention to solve the above problems and provide a process for producing a liquid crystal elemental device free from the influence of a spacer on both effective pixel portions and non-effective pixel portions from the viewpoint of display and excellent in display quality without an increase in cost.
The above object can be achieved by the present invention described below.
According to the present invention, there is thus provided a process for producing a liquid crystal elemental device comprising a pair of substrates arranged in opposed relation to each other through a spacer and a liquid crystal held in a space between the substrates, which comprises the steps of applying a spacer-forming material onto one of the pair of substrates by an ink-jet system to form the spacer, arranging the pair of substrates in opposed relation to each other with the spacer held therebetween, and enclosing a liquid crystal compound in the space between the pair of substrates.
According to the present invention, there is also provided a process for producing a liquid crystal elemental device comprising a pair of substrates arranged in opposed relation to each other through a spacer and a liquid crystal held in a space between the substrates, which comprises the steps of applying a spacer-forming material a plurality of times to be built up onto one of the pair of substrates to form the spacer, arranging the pair of substrates in opposed relation to each other with the spacer held therebetween, and enclosing a liquid crystal compound in the space between the pair of substrates.
According to the present invention, there is further provided a process for producing a liquid crystal elemental device comprising a pair of substrates arranged in opposed relation to each other through a spacer and a liquid crystal held in a space between the substrates, which comprises the steps of applying a spacer-forming material onto one of the pair of substrates to form the spacer, flattening the top of the spacer, arranging the pair of substrates in opposed relation to each other with the spacer held therebetween, and enclosing a liquid crystal compound in the space between the pair of substrates.
According to the present invention, there is still further provided a process for producing a spacer-bearing substrate, which comprises the steps of forming a colored layer on a substrate, and applying a spacer-forming material by an ink-jet system to form a spacer.
According to the present invention, there is yet still further provided a process for producing a spacer-bearing substrate, which comprises the step of applying a spacer-forming material a plurality of times to be built up onto a substrate to form a spacer.
According to the present invention, there is yet still further provided a process for producing a spacer-bearing substrate, which comprises the steps of forming a spacer composed of a spacer-forming material on a substrate and flattening the top of the spacer.